On 22/06/2015 9:15 p.m., Kagamin wrote:
On Monday, 22 June 2015 at 08:45:38 UTC, Andrea Fontana wrote:
They used to pack alpha informations with other pixel infos (color)
just for simplicity and to have a convenient way to store info inside
a file, I guess.
Separate mask has an advantage of lower memory consumption: it can have
1-bit depth. It was important in 90s when you didn't have lots of RAM
and HDD and didn't need transparency deeper than 1 bit, masks were used
to only outline a crop region, which worked with RLE compression well
further decreasing mask size, so it made no sense to waste space on
8-bit alpha channel.
Thank you. That use case does make sense.
I think I might add it as an optional feature anyway. For e.g. embedded
devices. The mutation algorithms can reasonably easily handle this
specific case in image storage.
